I do run my Bathroom fan before turning on the shower and toilet usage. I have you tubed the ventilation thing for humidity control and several winter campers state to leave it cracked open. Two thoughts on this (winter camping): 1) The DW leaves it cracked open due to condensation forming on the metal lid and then dripping on her during her potty time. 2) We use a whole house dehumidifier when cool, raining, and or usage of ceramic heaters (minimum air flow). First clue is condensation that will form on the windows. We have to dump the water tank on it daily or when we get up and before going to bed. Hope this helps! Happy winter camping!!!
Don & Dona W/yorkies Gizmo, Master Chief, & Tali
2011 Flagstaff 8528 BHSS 2015 Ford 6.7 XLT
2010 Full Timers & Still Going